Smudge-resistant glass articles and methods for making and using same

ABSTRACT

Described herein are coated glass or glass-ceramic articles having improved smudge resistance. Further described are methods of making and using the improved articles. The coated articles generally include a glass or glass-ceramic substrate and an oleophilic coating disposed thereon. The oleophilic coating is not a free-standing adhesive film, but a coating that is formed on or over the glass or glass-ceramic substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § 119 ofU.S. Provisional Application Ser. No. 61/563,200 filed on Nov. 23, 2011the contents of which are relied upon and incorporated herein byreference in their entirety as if fully set forth below.

TECHNICAL FIELD

The present disclosure relates generally to smudge-resistant oranti-smudge coatings. More particularly, the various embodimentsdescribed herein relate to glass or glass-ceramic articles havingoleophilic coatings disposed thereon such that the coated articlesexhibit improved smudge-resistance, as well as to methods of making andusing the coated articles.

BACKGROUND

Touch-activated or -interactive devices, such as screen surfaces (e.g.,surfaces of electronic devices having user-interactive capabilities thatare activated by touching specific portions of the surfaces), havebecome increasingly more prevalent. In general, these surfaces shouldexhibit high optical transmission, low haze, and high durability, amongother features. As the extent to which the touch screen-basedinteractions between a user and a device increases, so too does thelikelihood of fingerprint residue adversely affecting the touch screensurface.

Fingerprint residue, which can include not only natural fingerprint- orfingerborne-oils or grease, but also dirt, cosmetics, handcreams/lotions, or the like coupled therewith, can render a touch screen(or any other aesthetic or functional) surface unsightly and/or lessuser-friendly or functional. Further, an accumulation of such residuecan lead to a distortion in the transmission and haze properties of thetouch screen surface. That is, as a user contacts and operates the touchscreen surface, fingerprint residue is transferred to the surface. Whena fingerprint residue-rich region of the surface is subsequentlymanipulated, the fingerprint residue can smudge or smear across thesurface. These smudges and smear marks are visible to the naked eye, andcan affect how an image from the touch screen surface is observed by auser. With significant build-up, in some cases, these smudges and smearmarks can interfere with the function of a device by obscuring objectsthat must be seen for use and/or transmission of information into orfrom the device.

To combat the deleterious effects of fingerprint residue transfer (orother undesirable residue transfer), numerous so-called“anti-fingerprint” or “fingerprint-resistant” technologies have beendeveloped. These technologies generally involve making a modification tothe touch screen surface and/or applying a coating or film to the touchscreen surface to render the surface both hydrophobic and oleophobic.The aim of such approaches is towards preventing the transfer offingerprint residue in the first place, while also enabling easy removalof any residue that ultimately is transferred. Unfortunately, whilethese technologies may improve the fingerprint “soiling” resistance ofsome touch screen or other surfaces, the improvements generally are atthe expense of other features. For example, certain hydrophobic andoleophobic coating materials can cause a decrease in transmission, anincrease in haze, and/or a decrease in scratch resistance relative tothe uncoated touch screen surface.

Rather than focus on preventing fingerprint residue transfer as withanti-fingerprint technologies, a few alternative technologies havesought “anti-smudge” or “smudge-resistant” features, wherein the aim istowards enabling, or even promoting, fingerprint residue transfer. Thetransferred fingerprint residue can become hidden to the naked eyebecause it wets or coats the surface, instead of smudging or smearing,but can also be removed in a relatively easy fashion (e.g., by wipingwith a cloth). Just as with anti-fingerprint technologies, however,existing smudge-resistant technologies are often accompanied bysacrifices in other desirable features (e.g., transmission, haze,strength, scratch resistance, and the like).

There accordingly remains a need for technologies that provide touchscreen and other aesthetic or functional surfaces with improvedresistance against the adverse effects of fingerprint or otherundesirable residue. It would be particularly advantageous if suchtechnologies did not adversely affect other desirable properties of thesurfaces (e.g., transmission, haze, strength, scratch resistance, andthe like). It is to the provision of such technologies that the presentdisclosure is directed.

BRIEF SUMMARY

Described herein are various articles that have improved smudgeresistance, along with methods for their manufacture and use.

One type of coated article can include a glass or glass-ceramicsubstrate, and an oleophilic coating having an average thickness of lessthan or equal to about 100 nanometers disposed on at least a portion ofa surface of the glass or glass-ceramic substrate. The coated articlecan have a first optical transmittance and a first haze after a firsttouch-and-wipe cycle (where each touch-and-wipe cycle includes tactilelycontacting a portion of the coated article with a tactilely-transferredresidue or other undesirable residue and subsequently tactilely wipingat least the portion) and a second optical transmittance and a secondhaze after undergoing a number of touch-and-wipe cycles, such that thefirst optical transmittance and the second optical transmittance can besubstantially similar and/or the first haze and the second haze can besubstantially similar when the number of touch-and-wipe cycles is atleast 20. For example, in some situations, the second opticaltransmittance can be within 3 percent of the first optical transmittancewhen the number of touch-and-wipe cycles is at least 20 and/or thesecond haze can be within 5 percent of the first haze when the number oftouch-and-wipe cycles is at least 20.

Similarly, a mass of tactilely-transferred residue remaining on thecoated article after at least 20 touch-and-wipe cycles can besubstantially similar to a mass of tactilely-transferred residueremaining on the coated article after the first touch-and-wipe cycle.For example, it is possible for the mass of tactilely-transferredresidue remaining on the coated article after at least 20 touch-and-wipecycles to be within 0.4 milligrams of the mass of tactilely-transferredresidue remaining on the coated article after the first touch-and-wipecycle.

In some implementations of this type of coated article, there can be anintermediate layer that is interposed between the glass or glass-ceramicsubstrate and the oleophilic coating. The intermediate layer can includea reflection-resistant coating, a glare-resistant coating, acolor-providing composition, or the like.

With respect to the substrate of this type of coated article, in somecases, it can be formed from a silicate glass, borosilicate glass,aluminosilicate glass, boroaluminosilicate glass, or similar glass. Inother cases, the substrate can be formed from a glass-ceramic comprisinga glassy phase and a ceramic phase, where the ceramic phase includesβ-spodumene, β-quartz, nepheline, kalsilite, carnegieite, or a similarceramic material. In some applications, the glass or glass-ceramicsubstrate can have an average thickness of less than or equal to about 2millimeters.

With respect to the oleophilic coating of this type of coated article,in some cases, it can be formed from an uncured or partially-curedsiloxane comprising an organic side chain. For example, such materialsinclude partially-cured linear alkyl siloxanes, one example of which isa partially-cured linear alkyl siloxane is a partially-cured methylsiloxane.

Applications for, or uses of, this type of coated article includeforming a portion of a touch-sensitive display screen or cover plate foran electronic device, a non-touch-sensitive component of an electronicdevice, a surface of a household appliance, a surface of a vehiclecomponent, or the like.

Another type of coated article can include a glass or glass-ceramicsubstrate, and an oleophilic coating having an average thickness of lessthan or equal to about 100 nanometers disposed on at least a portion ofa surface of the glass or glass-ceramic substrate. The oleophiliccoating can include a partially-cured siloxane having a plurality ofpendant hydroxyl groups. A concentration of the pendant hydroxyl groupsin the partially-cured siloxane of the oleophilic coating can be atleast about 25 percent of a concentration of any pendant hydrogen andhydrocarbon groups in the partially-cured siloxane.

A contact angle between a drop of oleic acid and the oleophilic coatingcan be about 20° to about 40°. A contact angle between a drop ofethylene glycol and the oleophilic coating can be about 45° to about65°. A contact angle between a drop of hexadecane and the oleophiliccoating can be about 15° to about 30°. A contact angle between a drop ofwater and the oleophilic coating can be about 70° to about 100°.

In some implementations of this type of coated article, there can be anintermediate layer that is interposed between the glass or glass-ceramicsubstrate and the oleophilic coating. The intermediate layer can includea reflection-resistant coating, a glare-resistant coating, acolor-providing composition, or the like.

With respect to the substrate of this type of coated article, in somecases, it can be formed from a silicate glass, borosilicate glass,aluminosilicate glass, boroaluminosilicate glass, or similar glass. Inother cases, the substrate can be formed from a glass-ceramic comprisinga glassy phase and a ceramic phase, where the ceramic phase includesβ-spodumene, β-quartz, nepheline, kalsilite, carnegieite, or a similarceramic material. In some applications, the glass or glass-ceramicsubstrate can have an average thickness of less than or equal to about 2millimeters.

In certain implementations of this type of method, the concentration ofthe pendant hydroxyl groups in the partially-cured siloxane of theoleophilic coating is greater than or equal to the concentration of anypendant hydrogen and hydrocarbon groups in the partially-cured siloxane.

According to a Wu model, a polar component of a surface energy, adisperse component of the surface energy, and a total surface energy ofthe coated article can be about 6 milliJoules per square meter to about15 milliJoules per square meter, about 20 milliJoules per square meterto about 30 milliJoules per square meter, and about 26 milliJoules persquare meter to about 45 milliJoules per square meter, respectively.

According to a Fowkes model, a polar component of a surface energy, adisperse component of the surface energy, and a total surface energy ofthe coated article can be about 4 milliJoules per square meter to about10 milliJoules per square meter, about 20 milliJoules per square meterto about 35 milliJoules per square meter, and about 24 milliJoules persquare meter to about 45 milliJoules per square meter, respectively.

According to an Owens-Wendt model, a polar component of a surfaceenergy, a disperse component of the surface energy, and a total surfaceenergy of the coated article can be about 5 milliJoules per square meterto about 10 millijoules per square meter, about 20 millijoules persquare meter to about 30 millijoules per square meter, and about 25millijoules per square meter to about 40 millijoules per square meter,respectively.

This type of coated article can have a first optical transmittance and afirst haze after a first touch-and-wipe cycle (where each touch-and-wipecycle includes tactilely contacting a portion of the coated article witha tactilely-transferred residue or other undesirable residue andsubsequently tactilely wiping at least the portion) and a second opticaltransmittance and a second haze after undergoing a number oftouch-and-wipe cycles, such that the first optical transmittance and thesecond optical transmittance can be substantially similar and/or thefirst haze and the second haze can be substantially similar when thenumber of touch-and-wipe cycles is at least 20. For example, in somesituations, the second optical transmittance can be within 3 percent ofthe first optical transmittance when the number of touch-and-wipe cyclesis at least 20 and/or the second haze can be within 5 percent of thefirst haze when the number of touch-and-wipe cycles is at least 20.

Similarly, a mass of tactilely-transferred residue remaining on thecoated article after at least 20 touch-and-wipe cycles can besubstantially similar to a mass of tactilely-transferred residueremaining on the coated article after the first touch-and-wipe cycle.For example, it is possible for the mass of tactilely-transferredresidue remaining on the coated article after at least 20 touch-and-wipecycles to be within 0.4 milligrams of the mass of tactilely-transferredresidue remaining on the coated article after the first touch-and-wipecycle.

In certain implementations of this type of coated article, wherein theglass or glass-ceramic substrate is a chemically strengthened glass orglass-ceramic substrate comprising a layer under compression thatextends from the surface of the glass or glass-ceramic substrate inwardto a selected depth. In such implementations, a compressive stress ofthe layer under compression can be about 400 megaPascals to about 1200megaPascals, and the depth of the layer under compression can be about30 micrometers to about 80 micrometers.

Applications for, or uses of, this type of coated article includeforming a portion of a touch-sensitive display screen or cover plate foran electronic device, a non-touch-sensitive component of an electronicdevice, a surface of a household appliance, a surface of a vehiclecomponent, or the like.

Yet another type of coated article can include a chemically-strengthenedalkali aluminosilicate glass substrate having a layer under compressionthat extends from a surface of the glass or glass-ceramic substrateinward to a selected depth, and a partially-cured methyl siloxaneoleophilic coating having an average thickness of less than or equal toabout 50 nanometers disposed directly on at least a portion of a surfaceof the chemically-strengthened alkali aluminosilicate glass substrate.The partially-cured methyl siloxane oleophilic coating of type of coatedarticle can have a plurality of pendant hydroxyl groups, such that aconcentration of the pendant hydroxyl groups in the partially-curedmethyl siloxane of the oleophilic coating is at least about 50 percentof a concentration of any pendant hydrogen and methyl groups in thepartially-cured methyl siloxane. This type of coated article can have afirst optical transmittance and a first haze after a firsttouch-and-wipe cycle (where each touch-and-wipe cycle includes tactilelycontacting a portion of the coated article with a tactilely-transferredresidue and subsequently tactilely wiping at least the portion) and asecond optical transmittance and a second haze after undergoing a numberof touch-and-wipe cycles, such that the first optical transmittance andthe second optical transmittance are within 2 percent when the number oftouch-and-wipe cycles is at least 20 and the first haze and the secondhaze are within 3 percent when the number of touch-and-wipe cycles is atleast 20.

With this type of article, a mass of tactilely-transferred residueremaining on the coated article after at least 20 touch-and-wipe cyclescan be within 0.3 milligrams of a mass of tactilely-transferred residueremaining on the coated article after the first touch-and-wipe cycle.

A contact angle between a drop of oleic acid and the oleophilic coatingcan be about 25° to about 32°, a contact angle between a drop ofethylene glycol and the oleophilic coating is about 52° to about 60°, acontact angle between a drop of hexadecane and the oleophilic coating isabout 21° to about 28°, and/or a contact angle between a drop of waterand the oleophilic coating is about 77° to about 82°.

One type of method for making a coated article can includes forming anoleophilic coating having an average thickness of less than or equal toabout 100 nanometers on at least a portion of a surface of a glass orglass-ceramic substrate.

In certain cases, the method can further include forming an intermediatelayer on at least a portion of the surface of the glass or glass-ceramicsubstrate prior to forming the oleophilic coating, wherein theintermediate layer includes a reflection-resistant coating, aglare-resistant coating, or a color-providing composition.

In certain implementations, the forming step comprises forming apartially-cured siloxane comprising a plurality of pendant hydroxylgroups, wherein a concentration of the pendant hydroxyl groups in thepartially-cured siloxane of the oleophilic coating is at least about 25percent of a concentration of any pendant hydrogen and hydrocarbongroups in the partially-cured siloxane.

It is to be understood that both the foregoing brief summary and thefollowing detailed description describe various embodiments and areintended to provide an overview or framework for understanding thenature and character of the claimed subject matter. The accompanyingdrawings are included to provide a further understanding of the variousembodiments, and are incorporated into and constitute a part of thisspecification. The drawings illustrate the various embodiments describedherein, and together with the description serve to explain theprinciples and operations of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the visual smudge characteristics of two coated glassarticles as seen under standard lighting conditions in accordance withEXAMPLE 6.

FIG. 2 illustrates the visual smudge characteristics of two coated glassarticles as seen under an ultraviolet lamp in accordance with EXAMPLE 6.

FIG. 3 is a graphical representation of the amount of syntheticfingerprint residue mass that was transferred to various coated glassarticles relative to the number of touch-and-wipe cycles performedthereon in accordance with EXAMPLE 7.

FIG. 4 is a graphical representation of the haze of various coated glassarticles relative to the number of touch-and-wipe cycles performedthereon in accordance with EXAMPLE 7.

FIG. 5 illustrates the visual smudge characteristics of various coatedglass articles relative to the number of touch-and-wipe cycles performedthereon as seen under standard lighting conditions in accordance withEXAMPLE 7.

FIG. 6 is a graphical representation of the amount of syntheticfingerprint residue mass that was transferred to various coated glassarticles relative to the number of touch-and-wipe cycles performedthereon in accordance with EXAMPLE 8.

FIG. 7 is a graphical representation of the haze of various coated glassarticles relative to the number of touch-and-wipe cycles performedthereon in accordance with EXAMPLE 8.

These and other aspects, advantages, and salient features will becomeapparent from the following detailed description, the accompanyingdrawings, and the appended claims.

DETAILED DESCRIPTION

Referring now to the figures, wherein like reference numerals representlike parts throughout the several views, exemplary embodiments will bedescribed in detail. Throughout this description, various components maybe identified having specific values or parameters. These items,however, are provided as being exemplary of the present disclosure.Indeed, the exemplary embodiments do not limit the various aspects andconcepts, as many comparable parameters, sizes, ranges, and/or valuesmay be implemented. Similarly, the terms “first,” “second,” “primary,”“secondary,” “top,” “bottom,” “distal,” “proximal,” and the like, do notdenote any order, quantity, or importance, but rather are used todistinguish one element from another. Further, the terms “a,” “an,” and“the” do not denote a limitation of quantity, but rather denote thepresence of “at least one” of the referenced item.

Described herein are various articles that have improved resistance tothe adverse effects observed when tactilely-transferred residue issmudged, along with methods for their manufacture and use. The improvedarticles generally include a glass or glass-ceramic substrate and anoleophilic coating disposed directly or indirectly thereon. Theoleophilic coatings, which can be hydrophobic or hydrophilic,beneficially provide the articles with improved smudge resistancerelative to similar or identical articles that lack the oleophiliccoating. In addition, and as will be described in more detail below, thecoated articles can exhibit high transmission, low haze, and highdurability, among other features, both before and after application oftactilely-transferred residue thereto.

As used herein, the terms “anti-smudge” or “smudge-resistant” generallyrefer to the ability of a surface having tactilely-transferred residuecontained thereon to resist the visible smudging or smearing of theexisting tactilely-transferred residue during subsequent user contactwith the surface by hiding/obscuring the tactilely-transferred residueon the surface and/or by removing the tactilely-transferred residue fromthe surface. Therefore, a smudge-resistant surface must at leastpartially enable tactilely-transferred residue to be transferredthereto.

In addition, the term “oleophilic” is used herein to refer to a materialthat imparts a wetting characteristic such that the contact anglebetween oleic acid and a surface formed from the material is less than90 degrees (°). Analogously, the term “hydrophilic is used herein torefer to a material that imparts a wetting characteristic such that thecontact angle between water and a surface formed from the material isless than 90°. In contrast, the term “hydrophobic is used herein torefer to a material that imparts a wetting characteristic such that thecontact angle between water and a surface formed from the material isgreater than 90°.

Further, the term “tactilely-transferred residue” is used herein forconvenience to generically refer to and encompass any undesirableresidue that is contacted with, and transferred to, a surface by a givenuser. This includes natural human-oils or grease, as well as any othermaterials coupled therewith (e.g., dirt, cosmetics, food particles, handcreams/lotions, or the like) that are contacted with, and transferredto, the surface via a finger, palm, wrist, forearm/elbow (e.g., when anappliance door is closed or otherwise manipulated by a forearm or anelbow), or other body part.

As stated above, the substrate on which the oleophilic coating isdirectly or indirectly disposed can comprise a glass or glass-ceramicmaterial. The choice of glass or glass-ceramic material is not limitedto a particular composition, as improved smudge-resistance can beobtained using a variety of glass or glass-ceramic compositions. Forexample, with respect to glasses, the material chosen can be any of awide range of silicate, borosilicate, aluminosilicate, orboroaluminosilicate glass compositions, which optionally can compriseone or more alkali and/or alkaline earth modifiers. By way ofillustration, one such glass composition includes the followingconstituents: 58-72 mole percent (mol %) SiO₂; 9-17 mol % Al₂O₃; 2-12mol % B₂O₃; 8-16 mol % Na₂O; and 0-4 mol % K₂O, wherein the ratio

${\frac{{{Al}_{2}{O_{3}\left( {{mol}\mspace{14mu}\%} \right)}} + {B_{2}{O_{3}\left( {{mol}\mspace{14mu}\%} \right)}}}{\sum\mspace{14mu}{{modifiers}\mspace{14mu}\left( {{mol}\mspace{14mu}\%} \right)}} > 1},$where the modifiers comprise alkali metal oxides. Another glasscomposition includes the following constituents: 61-75 mol % SiO₂; 7-15mol % Al₂O₃; 0-12 mol % B₂O₃; 9-21 mol % Na₂O; 0-4 mol % K₂O; 0-7 mol %MgO; and 0-3 mol % CaO. Another illustrative glass composition includesthe following constituents: 60-70 mol % SiO₂; 6-14 mol % Al₂O₃; 0-15 mol% B₂O₃; 0-15 mol % Li₂O; 0-20 mol % Na₂O; 0-10 mol % K₂O; 0-8 mol % MgO;0-10 mol % CaO; 0-5 mol % ZrO₂; 0-1 mol % SnO₂; 0-1 mol % CeO₂; lessthan 50 parts per million (ppm) As₂O₃; and less than 50 ppm Sb₂O₃;wherein 12 mol %≤Li₂O+Na₂O+K₂O≤20 mol % and 0 mol % MgO+CaO≤10 mol %.Another illustrative glass composition includes the followingconstituents: 55-75 mol % SiO2, 8-15 mol % Al₂O₃, 10-20 mol % B₂O₃; 0-8%MgO, 0-8 mol % CaO, 0-8 mol % SrO and 0-8 mol % BaO. Yet anotherillustrative glass composition includes the following constituents: atleast one of Al₂O₃ or B₂O₃ and at least one of an alkali metal oxide oran alkali earth metal oxide, wherein −15 mol %(R₂O+R′O−Al₂O₃−ZrO₂)−B₂O₃≤4 mol %, where R can be Li, Na, K, Rb, and/orCs, and R′ can be Mg, Ca, Sr, and/or Ba. For example, one specificcomposition of this type includes from about 62 mol % to about 70 mol %SiO₂; from 0 mol % to about 18 mol % Al₂O₃; from 0 mol % to about 10 mol% B₂O₃; from 0 mol % to about 15 mol % Li₂O; from 0 mol % to about 20mol % Na₂O; from 0 mol % to about 18 mol % K₂O; from 0 mol % to about 17mol % MgO; from 0 mol % to about 18 mol % CaO; and from 0 mol % to about5 mol % ZrO₂. Yet another illustrative glass composition includes thefollowing constituents: SiO₂, Al₂O₃, P₂O₅, and at least one alkali metaloxide (R₂O), wherein 0.75≤[(P₂O₅(mol %)+R₂O(mol %))/M₂O₃ (mol %)]≤1.2,where M₂O₃=Al₂O₃+B₂O₃. Yet another illustrative glass compositionincludes the following constituents: at least about 4 mol % P₂O₅,wherein (M₂O₃(mol %)/R_(x)O(mol %))<1, wherein M₂O₃=Al₂O₃+B₂O₃, andwherein R_(x)O is the sum of monovalent and divalent cation oxidespresent in the glass. Still another illustrative glass compositionincludes the following constituents: at least about 50 mol % SiO₂, fromabout 9 mol % to about 22 mol % Al₂O₃; from about 4.5 mol % to about 10mol % B₂O₃; from about 10 mol % to about 20 mol % Na₂O; from 0 mol % toabout 5 mol % K₂O; at least about 0.1 mol % MgO and/or ZnO, wherein0≤MgO+ZnO≤6; and, optionally, at least one of CaO, BaO, and SrO, wherein0 mol %≤CaO+SrO+BaO≤2 mol %.

Similarly, with respect to glass-ceramics, the material chosen can beany of a wide range of materials having both a glassy phase and aceramic phase. Illustrative glass-ceramics include those materials wherethe glass phase is formed from a silicate, borosilicate,aluminosilicate, or boroaluminosilicate, and the ceramic phase is formedfrom β-spodumene, β-quartz, nepheline, kalsilite, or carnegieite.

The glass or glass-ceramic substrate can adopt a variety of physicalforms. That is, from a cross-sectional perspective, the substrate can beflat or planar, or it can be curved and/or sharply-bent. Similarly, itcan be a single unitary object, or a multi-layered structure orlaminate. Further, the substrate optionally can be annealed and/orstrengthened (e.g., by thermal tempering, chemical ion-exchange, or likeprocesses).

The oleophilic coating that is disposed, either directly or indirectly,on at least a portion of a surface of the substrate can be formed from avariety of materials, termed “coating precursor materials” herein forconvenience only. The coating precursor material and the finaloleophilic coating generally can include an organic component to providethe requisite oleophilicity, as well as an inorganic component toprovide the ability to strongly bond to the surface of the glass orglass-ceramic substrate. The coating precursor material, and, byextension, the final oleophilic coating produced therefrom, will also beselected such that it imparts other desirable properties (e.g.,appropriate levels of haze, transmittance, durability, and the like) tothe final coated article both before and after fingerprint residue hasbeen applied thereto.

Exemplary coating precursor materials that can be used to form theoleophilic coating include uncured and partially-cured siloxanes havingorganic side chains (e.g., silsesquioxanes or silicones). For thepurposes of the present disclosure, these coating precursor materialscan be designated by the general formula [—R₂SiO—]_(n), wherein each Rin the n repeat groups is independently a hydrogen, hydroxyl, orhydrocarbon group or moiety, with the proviso that not all of the Rgroups in the n repeat units are hydrogen or hydroxyl. The hydrocarbongroup can be a substituted or unsubstituted, linear or branched, chainor cyclic structure having between 1 and 22 carbons. It is importantthat these materials are not fully cured prior to their application tothe substrate, because a fully cured material will not be able tochemically bond to the glass or glass-ceramic substrate, nor be able tobe applied thinly One illustrative class of such coating precursormaterials includes partially-cured linear alkyl siloxanes (e.g.,partially-cured methyl siloxane, partially-cured ethyl siloxane,partially-cured propyl siloxane, and the like).

When such a coating precursor material is used, the oleophilic coatingitself generally will include an at-least-partially-cured siloxane. Inmany implementations involving an uncured or partially-cured siloxanehaving organic side chains as the coating precursor material, the finaloleophilic coating will be only partially cured. That is, not all of thehydroxyl pendant groups or moieties on the silicon atoms in the coatingprecursor material will participate in a condensation reaction (i.e.,such that they, along with the pendant hydrogen or hydrocarbon “R”groups or moieties of the general structure defined above, are removedfrom a siloxane unit during the combination of two separate siloxaneunits).

Indeed, in such implementations, it is desirable for the partially-curedsiloxane of the oleophilic coating to include a plurality of pendanthydroxyl groups. Surprisingly, the presence of increased amounts ofhydroxyl groups on the silicon atoms in the partially-cured siloxane ofthe oleophilic coating result in greater oleophilicity than afully-cured siloxane having essentially no hydroxyl groups on thesilicon atoms. Thus, in many of these embodiments, a concentration ofpendant hydroxyl groups in the partially-cured siloxane of theoleophilic coating can be at least about 25 percent of the concentrationof any pendant hydrogen and hydrocarbon groups in the partially-curedsiloxane of the oleophilic coating, when measured for example by nuclearmagnetic resonance spectroscopy (NMR). In certain cases, (e.g., whenhigher extents of oleophilicity are desired) the concentration ofpendant hydroxyl groups in the partially-cured siloxane of theoleophilic coating can be at least about 60 percent of the concentrationof any pendant hydrogen and hydrocarbon groups in the partially-curedsiloxane of the oleophilic coating. Finally, in certain situations(e.g., when even higher extents of oleophilicity are desired) theconcentration of pendant hydroxyl groups in the partially-cured siloxaneof the oleophilic coating can be greater than or equal to about theconcentration of any pendant hydrogen and hydrocarbon groups in thepartially-cured siloxane of the oleophilic coating.

In certain embodiments, the coated articles can include a layerinterposed between the glass or glass-ceramic substrate and theoleophilic coating material. This intermediate layer can be used toprovide additional features to the coated article (e.g., reflectionresistance or anti-reflection properties, glare resistance or anti-glareproperties, color, opacity, and/or the like) and can cover a portion ofthe substrate surface or the entire substrate surface on which theoleophilic coating is disposed. In one implementation, the intermediatelayer includes a coating of SiO₂ nanoparticles bound to at least aportion of the substrate to provide reflection resistance to the finalcoated article. In another implementation, the intermediate layer mightcomprise a multi-layered reflection-resistant coating formed fromalternating layers of polycrystalline TiO₂ and SiO₂. In anotherimplementation, the intermediate layer might comprise a color-providingcomposition that comprises a dye or pigment material.

Methods of making the above-described coated articles generally includethe steps of providing a glass or glass-ceramic substrate, and formingthe oleophilic coating on at least a portion of a surface of thesubstrate. In those embodiments where the optional intermediate layer isimplemented, however, the methods generally involve an additional stepof forming the intermediate layer on at least a portion of a surface ofthe substrate prior to the formation of the oleophilic coating. Itshould be noted that when the intermediate layer is implemented, thesurface fraction of the substrate that is covered by the oleophiliccoating does not have to be the same as the surface fraction covered bythe intermediate layer.

The selection of materials used in the glass or glass-ceramicsubstrates, oleophilic coatings, and optional intermediate layers can bemade based on the particular application desired for the final coatedarticle. In general, however, the specific materials will be chosen fromthose described above for the coated articles.

Provision of the substrate can involve selection of a glass orglass-ceramic object as-manufactured, or it can entail subjecting theas-manufactured glass or glass-ceramic object to a treatment inpreparation for forming the optional intermediate layer or theoleophilic coating. Examples of such pre-coating treatments includephysical or chemical cleaning, physical or chemical strengthening,physical or chemical etching, physical or chemical polishing, annealing,shaping, and/or the like. Such processes are known to those skilled inthe art to which this disclosure pertains.

Once the glass or glass-ceramic substrate has been selected and/orprepared, either the optional intermediate layer or the oleophiliccoating can be disposed thereon. Depending on the materials chosen,these coatings can be formed using a variety of techniques. It isimportant to note that the coatings described herein (i.e., both theoptional intermediate layer and the oleophilic coating) are notfree-standing films that can be applied (e.g., via an adhesive or otherfastening means) to the surface of the substrate, but are, in fact,physically formed on the surface of the substrate.

In general, the optional intermediate layer and/or the oleophiliccoating can be fabricated independently using any of the variants ofchemical vapor deposition (CVD) (e.g., plasma-enhanced CVD,aerosol-assisted CVD, metal organic CVD, and the like), any of thevariants of physical vapor deposition (PVD) (e.g., ion-assisted PVD,pulsed laser deposition, cathodic arc deposition, sputtering, and thelike), spray coating, spin-coating, dip-coating, inkjetting, sol-gelprocessing, or the like. Such processes are known to those skilled inthe art to which this disclosure pertains.

In many implementations, the materials used to form optionalintermediate layer and/or the oleophilic coating may need to undergo anadditional treatment step to finalize these layers. By way of example,in cases when the oleophilic coating precursor material is applied tothe substrate in liquid form, it can undergo a thermal or radiationcuring step to form the final oleophilic coating. In those situationswhen the oleophilic coating precursor material is formed from a siloxanematerial, the curing step is generally a condensation reaction, whichresults in a structural rearrangement of the individual siloxane unitsto form a cage- or ladder-like structure. As described above, in many ofthese cases, the cage- or ladder-like structure will comprise an onlypartially cured siloxane.

Once the coated article is formed, it can be used in a variety ofapplications where the coated article will come into contact withfingerprint residue. These applications encompass touch-sensitivedisplay screens or cover plates for various electronic devices (e.g.,cellular phones, personal data assistants, computers, tablets, globalpositioning system navigation devices, and the like),non-touch-sensitive components of electronic devices, surfaces ofhousehold appliances (e.g., refrigerators, microwave ovens, stovetops,oven, dishwashers, washers, dryers, and the like), and vehiclecomponents, just to name a few devices that might be tactilelymanipulated or accessed.

Given the breadth of potential uses for the improved smudge-resistantcoated articles described herein, it should be understood that thespecific features or properties of a particular coated article willdepend on the ultimate application therefor or use thereof. Thefollowing description, however, will provide some generalconsiderations.

There is no particular limitation on the average thickness of thesubstrate contemplated herein. In many exemplary applications, howeverthe average thickness will be less than or equal to about 15 millimeters(mm). If the coated article is to be used in applications where it maybe desirable to optimize thickness for weight, cost, and strengthcharacteristics (e.g., in electronic devices, or the like), then eventhinner substrates (e.g., less than or equal to about 5 mm) can be used.By way of example, if the coated article is intended to function as acover for a touch screen display, then the substrate can exhibit anaverage thickness of about 0.02 mm to about 2.0 mm.

In contrast to the glass or glass-ceramic substrate, where thickness isnot limited, the average thickness of the oleophilic coating should beless than or equal to about 100 nanometers (nm). If the oleophiliccoating is much thicker than this, it will have adverse effects on thehaze, optical transmittance, scratch resistance, and/or durability ofthe final coated article. To illustrate, with thinner oleophiliccoatings, a potential scratch to the surface can be resisted better bythe more durable underlying substrate, because the scratch is actuallyabsorbed by the underlying substrate rather than the coating. If theoleophilic coating is thicker than 100 nm on average, then the scratchwill be absorbed by the coating itself and will be visible to the nakedeye. Thus, in applications where high scratch resistance is important orcritical (in addition to the improved smudge resistance provided by theoleophilic coating), the average thickness of the oleophilic coatingshould be less than or equal to 75 nm.

The thickness of the intermediate layer will be dictated by itsfunction. For glare and/or reflection resistance for example, theaverage thickness should be less than or equal to about 200 nanometers.Coatings that have an average thickness greater than this could scatterlight in such a manner that defeats the glare and/or reflectionresistance properties.

In general, the optical transmittance of the coated article will dependon the type of materials chosen. For example, if a glass orglass-ceramic substrate is used without any pigments added theretoand/or the oleophilic coating is sufficiently thin, the coated articlecan have a transparency over the entire visible spectrum of at leastabout 85%. In certain cases where the coated article is used in theconstruction of a touch screen for an electronic device, for example,the transparency of the coated article can be at least about 92% overthe visible spectrum. In situations where the substrate comprises apigment (or is not colorless by virtue of its material constituents)and/or the oleophilic coating is sufficiently thick, the transparencycan diminish, even to the point of being opaque across the visiblespectrum. Thus, there is no particular limitation on the opticaltransmittance of the coated article itself.

Like transmittance, the haze of the coated article can be tailored tothe particular application. As used herein, the terms “haze” and“transmission haze” refer to the percentage of transmitted lightscattered outside an angular cone of ±4.0° in accordance with ASTMprocedure D1003, the contents of which are incorporated herein byreference in their entirety as if fully set forth below. For anoptically smooth surface, transmission haze is generally close to zero.In those situations when the coated article is used in the constructionof a touch screen for an electronic device, the haze of the coatedarticle can be less than or equal to about 5%.

Similarly, the contact angle exhibited with respect to a variety offluids and/or the surface energy of the coated article can be tailoredto the particular application. As stated above, the term “oleophilic”refers to a material that imparts a wetting characteristic such that thecontact angle between oleic acid and a surface formed from the materialis less than 90 degrees (°). Thus, the coated article will exhibit acontact angle with oleic acid (i.e., a contact angle between a drop ofoleic acid and a surface thereof) that is less than 90°. In mostimplementations, however, the contact angle with oleic acid will beabout 20° and about 40°.

With respect to other fluids, the coated article will generally exhibita contact angle with, for example, ethylene glycol (i.e., a contactangle between a drop of ethylene glycol and a surface thereof) that isabout 45° to about 65°. In another example, the coated article willgenerally exhibit a contact angle with hexadecane (i.e., a contact anglebetween a drop of hexadecane and a surface thereof) that is about 15° toabout 30°. In yet another example, the coated article will generallyexhibit a contact angle with water (i.e., a contact angle between a dropof water and a surface thereof) that is about 70° to about 100°. For thepurposes of the present disclosure, such contact angles represent theaverage of 15 measurements made using a goniometer, where a droplet of agiven fluid (about 2 microliters for water, and about 4 microliters forthe organic fluids) is placed on five discrete locations on the surfaceof a coated article, and three different samples of a givenimplementation are measured.

The total surface energy of the coated article is determined by takingthe sum of the polar energy component and the dispersive energycomponent. For the purposes of the present disclosure, the surfaceenergy is estimated from contact angle measurements using various testliquids, such as those described immediately above, with varying surfacetensions using the KRÜSS Drop Shape Analysis program to run acalculation using models such as Wu, Fowkes, and Owens-Wendt. Whencalculating the surface energy according to each of these models, thesoftware calculates the polar component of the surface energy, thedisperse component of the surface energy, and the total surface energyaccording to each model using the parameters for these modelsestablished by the software program. These estimates are recorded foreach sample, and an average value across 5 samples is reported. Ingeneral, according to the Wu model, the polar component of the surfaceenergy, the disperse component of the surface energy, and the totalsurface energy of the coated articles described herein will generally beabout 6 to about 15 milliJoules per square meter (mJ/m²), about 20 toabout 30 mJ/m², and about 26 to about 45 mJ/m², respectively. Similarly,according to the Fowkes model, the polar component of the surfaceenergy, the disperse component of the surface energy, and the totalsurface energy of the coated articles described herein will generally beabout 4 to about 10 mJ/m², about 20 to about 35 mJ/m², and about 24 toabout 45 mJ/m², respectively. In addition, according to the Owens-Wendtmodel, the polar component of the surface energy, the disperse componentof the surface energy, and the total surface energy of the coatedarticles described herein will generally be about 5 to about 10 mJ/m²,about 20 to about 30 mJ/m², and about 25 to about 40 mJ/m²,respectively.

In implementations where the glass or glass-ceramic substrate isstrengthened, the substrate will have a layer under compression thatextends from a surface of the substrate itself inward to a selecteddepth. While each surface of the coated article's substrate can have alayer under compression, for the purposes of the present disclosure,when a substrate is described as having such a layer, the surface ofreference is at least that on which the oleophilic coating is disposed.The compressive stress (CS) of the layer under compression, and thedepth of this layer (DOL) can be measured using a glass or glass-ceramicsurface stress meter, which is an optical tool that generally uses thephotoelastic constant and index of refraction of the substrate materialitself, and converts the measured optical interference fringe patternsto specific CS and DOL values. In those situations when the coatedarticle is used in the construction of a touch screen for an electronicdevice, the CS and DOL of the coated article generally can be,respectively, about 400 megaPascals (MPa) to about 1200 MPa and about 30micrometers (μm) to about 80 μm. Importantly, in many implementations,the CS and DOL each do not change by more than about 5 percent after theoleophilic coating (including any optional intermediate layer(s)) isdisposed thereon.

Regardless of the application or use, the coated articles describedherein offer improved smudge-resistance relative to identical articlesthat lack the oleophilic coatings described herein. While smudgeresistance can appear to be a qualitative and potentially subjectivecharacterization, there are a number of quantifiable indications ofsmudge-resistance, examples of which will now be described.

One quantifiable indication of this improved smudge resistance can beseen in the net change in the amount of tactilely-transferred residuethat is transferred from a user to the article during use and thatremains after wiping the tactilely-transferred residue over time. Thatis, when a user tactilely interacts with the coated article, some amountof tactilely-transferred residue will transfer to the article. When thesame region of the coated article is subsequently smudged or wiped byfurther user interaction (and not with a cloth-like material), some ofthe tactilely-transferred residue is smeared over the coated article andsome other tactilely-transferred residue might be added, while some isremoved from the coated article. The mass of the tactilely-transferredresidue remaining on the coated article after each so-called“touch-and-wipe cycle” can be quantified, for example, by weighing themass thereof.

Given that any particular tactile interaction will involve any of avariety of different residue components/compositions, and that theapplied touch and wipe pressures can vary with each user, the change inthe amount of tactilely-transferred residue over time can be measured,compared, and analyzed using a standardized comparative procedure. Forthe purposes of the present disclosure, this procedure first entails theuse of a model fingerprint applicator, formed from a fingerprint stamp,to apply a commercially available synthetic sebum to the coated articleat a pressure of about 3 pounds per square inch (psi). This is followedby wiping the applied “fingerprint” using a Crockmeter or a linearabrader fitted with a Crockmeter kit. The wiping step is a modificationof the Crockmeter test that is described in ASTM test procedureF1319-94, entitled “Standard Test Method for Determination of Abrasionand Smudge Resistance of Images Produced from Business Copy Products,”the contents of which are incorporated herein by reference in theirentirety as if fully set forth below. Specifically, the Crockmeter orlinear abrader subjects the coated article to direct contact with aCrockmeter rubbing tip or “finger” mounted on the end of a weighted arm.Rather than using a standard crocking cloth, the tactile contact issimulated by a “finger” fitted with a portion of a nitrile laboratoryglove. The wiping step involves contacting the finger with the region ofthe coated article having the synthetic sebum-containing fingerprintwith a pressure of about 0.93 psi, and moving the finger back-and-forthacross the length of the coated article. After each touch-and-wipe cycleof this procedure, the mass of the coated article is recorded andcompared with the mass of the coated article prior to the firsttouch-and-wipe cycle.

In contrast to existing technologies, the amount of fingerprint residuethat remains on the coated articles described herein after a giventouch-and-wipe cycle (e.g., after 5, 10, 50, 100, or more cycles) can besubstantially similar to, or even less than, the amount of fingerprintresidue that remains on the coated articles after a first touch-and-wipecycle, as measured using the above-described procedure. In other words,the coated articles herein resist any significant buildup of visibleresidue during use. For example, in certain implementations, the changein fingerprint residue remaining on the coated articles described hereinafter 20 touch-and-wipe cycles, relative to the first cycle, can beabout ±0.4 milligrams (mg). In other implementations, the change infingerprint residue remaining on the coated articles described hereinafter 20 touch-and-wipe cycles, relative to the first cycle, can beabout ±0.1 mg.

Another quantifiable indication of the improved smudge resistance is thechange in haze that is observed over time. This change can be measuredusing the touch-and-wipe procedure described above, with the exceptionthat, rather than recording the mass of the coated article, the haze ofthe coated article is measured after each cycle of interest. In general,the overall haze of the coated articles described herein after a giventouch-and-wipe cycle can be substantially similar to, or even less than,the haze of the coated articles after the first touch-and-wipe cycle.Again, this indicates that the coated substrates and methods hereinprevent any significant buildup of visible residue and its deleterioussmudge characteristics during continued use and would tend to obviate orlessen a need for repeated and inconvenient cleaning by the user. Incertain implementations, the net change in the haze of the coatedarticles described herein after 20 touch-and-wipe cycles, relative tothe first cycle, can be about ±5%. In other implementations, the netchange in the haze of the coated articles described herein after 20touch-and-wipe cycles, relative to the first cycle, can be about ±2%.

Still another quantifiable indication of the improved smudge resistanceis the change in optical transmittance that is observed over time. Thischange can be measured using the touch-and-wipe procedure describedabove, with the exception that, rather than recording the mass of thecoated article, the optical transmittance of the coated article ismeasured after each cycle of interest. In general, the overalltransmittance of the coated articles described herein after a giventouch-and-wipe cycle can be substantially similar to, or even higherthan, the optical transmittance of the coated articles after the firsttouch-and-wipe cycle. In certain implementations, the net change in thetransmittance of the coated articles described herein after 20touch-and-wipe cycles, relative to the first cycle, can be about ±3%. Inother implementations, the net change in the transmittance of the coatedarticles described herein after 20 touch-and-wipe cycles, relative tothe first cycle, can be about ±0.5%.

In a specific embodiment that might be particularly advantageous forapplications such as touch accesses or operated electronic devices, asmudge resistant coated article is formed from a chemically strengthened(ion exchanged) alkali aluminosilicate flat glass sheet. The CS and DOLof the coated article can be, respectively, about 600 MPa to about 1000MPa and about 40 μm to about 70 μm. The oleophilic coating is formedfrom a partially-cured methyl siloxane coating precursor, and isdirectly coated on one surface of the glass sheet. The average thicknessof the glass sheet is less than or equal to about 1 mm, and the averagethickness of the methyl siloxane oleophilic coating is less than orequal to about 50 nm. The formed methyl siloxane oleophilic coating canhave a concentration of pendant hydroxyl groups that is at least about50 percent of the concentration of any pendant hydrogen and methylgroups therein. After formation of the oleophilic coating, the CS andDOL of the coated article change less than about 3% and about 1%,respectively.

Such a coated article can be used in the fabrication of a touch screendisplay for an electronic device. The coated article can have an initialoptical transmittance of at least about 94% and a haze of less than0.1%. The coated article can also have a contact angle with oleic acidthat is about 25° and about 32°. The coated article can also exhibit acontact angle with ethylene glycol that is about 52° to about 60°. Thecoated article can also exhibit a contact angle with hexadecane that isabout 21° to about 28°. The coated article can also exhibit a contactangle with water that is about 77° to about 82°.

According to the Wu model, the polar component of the surface energy,the disperse component of the surface energy, and the total surfaceenergy of this type of coated articles can be about 8 to about 14 mJ/m²,about 22 to about 26 mJ/m², and about 30 to about 40 mJ/m²,respectively. According to the Fowkes model, the polar component of thesurface energy, the disperse component of the surface energy, and thetotal surface energy of this type of coated article can be about 5 toabout 8 mJ/m², about 22 to about 26 mJ/m², and about 25 to about 33mJ/m², respectively. According to the Owens-Wendt model, the polarcomponent of the surface energy, the disperse component of the surfaceenergy, and the total surface energy of the coated articles describedherein will generally be about 6 to about 9 mJ/m², about 22 to about 25mJ/m², and about 27 to about 34 mJ/m², respectively.

During operation, the coated article can exhibit high smudge resistancein that a change in fingerprint residue remaining on the coated articleafter 20 touch-and-wipe cycles, relative to the first cycle, can beabout ±0.3 mg. In addition, the net change in the haze of the coatedarticle after 20 touch-and-wipe cycles, relative to the first cycle, canbe about ±3%. Further, the net change in the transmittance of the coatedarticle after 20 touch-and-wipe cycles, relative to the first cycle, canbe about ±2%.

In another specific embodiment, a smudge resistant coated article isformed from a chemically strengthened (ion-exchanged) alkalialuminosilicate flat glass sheet. The CS and DOL of the coated articlecan be, respectively, about 600 MPa to about 1000 MPa and about 40 μm toabout 70 μm. A reflection resistant layer, formed from SiO₂nanoparticles having an average diameter of about 20 nm, is coateddirectly on one surface of the glass sheet. The oleophilic coating isformed from a partially-cured methyl siloxane coating precursor, and isdirectly coated on the reflection resistant layer as a conformalcoating. The average thickness of the glass sheet is less than or equalto about 1 mm, the average thickness of the reflection resistant layeris less than or equal to about 50 nm, and the average thickness of themethyl siloxane oleophilic coating is less than or equal to about 50 nm.The formed methyl siloxane oleophilic coating can have a concentrationof pendant hydroxyl groups that is at least about 50 percent of theconcentration of any pendant hydrogen and methyl groups therein. Afterformation of the oleophilic coating, the CS and DOL of the coatedarticle change less than about 3% and about 1%, respectively.

Such a coated article can also be used in the fabrication of a touchscreen display for an electronic device. The coated article can have aninitial optical transmittance of at least about 95% and a haze of lessthan 0.2%. The coated article can also have a contact angle with oleicacid that is about 25° and about 32°. The coated article can alsoexhibit a contact angle with ethylene glycol that is about 52° to about60°. The coated article can also exhibit a contact angle with hexadecanethat is about 21° to about 28°. The coated article can also exhibit acontact angle with water that is about 77° to about 82°.

According to the Wu model, the polar component of the surface energy,the disperse component of the surface energy, and the total surfaceenergy of this type of coated articles can be about 8 to about 14 mJ/m²,about 22 to about 26 mJ/m², and about 30 to about 40 mJ/m²,respectively. According to the Fowkes model, the polar component of thesurface energy, the disperse component of the surface energy, and thetotal surface energy of this type of coated article can be about 5 toabout 8 mJ/m², about 22 to about 26 mJ/m², and about 25 to about 33mJ/m², respectively. According to the Owens-Wendt model, the polarcomponent of the surface energy, the disperse component of the surfaceenergy, and the total surface energy of the coated articles describedherein will generally be about 6 to about 9 mJ/m², about 22 to about 25mJ/m², and about 27 to about 34 mJ/m², respectively.

During operation, the coated article can exhibit high smudge resistancein that a change in fingerprint residue remaining on the coated articleafter 20 touch-and-wipe cycles, relative to the first cycle, can beabout ±0.2 mg. In addition, the net change in the haze of the coatedarticle after 20 touch-and-wipe cycles, relative to the first cycle, canbe about ±2%. Further, the net change in the transmittance of the coatedarticle after 20 touch-and-wipe cycles, relative to the first cycle, canbe about ±1%.

The various embodiments of the present disclosure are furtherillustrated by the following non-limiting examples.

EXAMPLES Example 1: Fabrication of Partially-Cured Oleophilic Coatingson Flat Glass Substrates

In this example, oleophilic coatings were prepared on flat glasssubstrates. The substrates chosen were chemically strengthened flatglass sheets having a nominal composition of 69.2 mol % SiO₂, 8.5 mol %Al₂O₃, 13.9 mol % Na₂O, 1.2 mol % K₂O, 6.5 mol % MgO, 0.5 mol % CaO, and0.2 mol % SnO₂.

To form the oleophilic coating, as-received Accuglass® T 11 (111,Honeywell) was diluted in isopropanol to form various solutions rangingfrom about 25 weight percent (wt %) to about 50 wt % methyl siloxane.These solutions were coated onto samples of the glass sheets using anautomated dip-coater. Typically, withdrawal speeds of about 25millimeters per minute (mm/min) to about 50 mm/min were used to form thecoatings. The dip-coated samples were cured by using the followingheating cycle: from room temperature, the temperature was ramped up toabout 80 degrees Celsius (° C.) at a rate of about 5 degrees Celsius perminute (° C./min), held at temperature for about 30 min, ramped at arate of about 5° C./min to about 130° C., held at temperature for about30 min, ramped at a rate of about 5° C./min to between about 180° C. andabout 300° C., held at temperature for about 1 hour, and ramped down toroom temperature at a rate of 10° C./min in air.

Example 2: Fabrication of Anti-Reflection Coatings and Partially-CuredOleophilic Coatings on Flat Glass Substrates

In this example, oleophilic coatings were prepared onanti-reflection-coated flat glass substrates. The substrates chosen werechemically strengthened flat glass sheets having a nominal compositionof 69.2 mol % SiO₂, 8.5 mol % Al₂O₃, 13.9 mol % Na₂O, 1.2 mol % K₂O, 6.5mol % MgO, 0.5 mol % CaO, and 0.2 mol % SnO₂.

To make the anti-reflection coatings, dispersions comprising SiO₂ and/orZrO₂ nanoparticles having a range of particle sizes between about 5 nmto about 100 nm in isopropanol or water (Nissan Chemical USA) wereapplied to samples of the glass sheets using an automated dip-coater.The concentrations of the solutions and withdrawal speed of theanti-reflection coatings were varied to achieve coatings of differentthicknesses.

An oleophilic coating was then applied to each sample the using theprocedure described in EXAMPLE 1.

Example 3: Fabrication of Partially-Cured Oleophilic Coatings on FlatGlass Substrates

In this example, oleophilic coatings having anti-reflection componentswere prepared on flat glass substrates. The substrates chosen werechemically strengthened flat glass sheets having a nominal compositionof 69.2 mol % SiO₂, 8.5 mol % Al₂O₃, 13.9 mol % Na₂O, 1.2 mol % K₂O, 6.5mol % MgO, 0.5 mol % CaO, and 0.2 mol % SnO₂.

Dispersions comprising SiO₂ nanoparticles having a size of less than orequal to about 20 nm in isopropanol (Nissan Chemical USA) were mixedinto the 50 wt % Accuglass® T 11 (111, Honeywell) solutions as preparedin EXAMPLE 1 such that the final concentration of SiO₂ in the solutionwas about 1 wt %. These solutions were coated onto the glass substratesusing the procedure described in EXAMPLE 1.

Comparative Example 4 Fabrication of Fluorosilane Coating on Flat GlassSubstrates

In this example, fluorosilane-coated glass samples were prepared usingthe procedures described in commonly-assigned U.S. patent applicationSer. No. 12/366,267, entitled “Damage Resistant Glass Article For Use AsA Cover Plate In Electronic Devices,” the contents of which areincorporated herein by reference in their entirety as if fully set forthbelow. Specifically, the substrates chosen were chemically strengthenedflat glass sheets having a nominal composition of 69.2 mol % SiO₂, 8.5mol % Al₂O₃, 13.9 mol % Na₂O, 1.2 mol % K₂O, 6.5 mol % MgO, 0.5 mol %CaO, and 0.2 mol % SnO₂. The fluorosilane used was alkoxysilylperfluoropolyether, which is commercially marketed as Dow CorningDC2604, as an “easy-to-clean” surface coating.

Comparative Example 5: Application of Free-Standing Anti-FingerprintFilms to Flat Glass Substrates

In this example, commercially available anti-fingerprint adhesive filmswere coated onto glass samples. The substrates chosen were chemicallystrengthened flat glass sheets having a nominal composition of 69.2 mol% SiO₂, 8.5 mol % Al₂O₃, 13.9 mol % Na₂O, 1.2 mol % K₂O, 6.5 mol % MgO,0.5 mol % CaO, and 0.2 mol % SnO₂. The adhesive films used were thosecommercially marketed by Steinheil as the SGP Steinheil Ultra Seriesfilms for display use.

Example 6: Visual Characterization of Coated Glass Samples

In this example, the smudge-resistance of various coated articles thatwere prepared in accordance with EXAMPLES 1 and 4 was compared. First,actual human fingerprints were applied to each glass sample. Next, thefingerprint residue left behind was wiped in a single direction acrossthe coated articles using the same fingers that were used to transferthe fingerprint residue.

The coated glass samples prepared in accordance with EXAMPLE 1 exhibitedsignificantly better smudge-resistance than those prepared in accordancewith COMPARATIVE EXAMPLE 4. FIG. 1 illustrates representative resultsfor this human touch- and wipe procedure under ordinary lightingconditions. As can be seen from FIG. 1, the glass sample having theoleophilic coating of EXAMPLE 1 (i.e., the sample on the right-hand sideof FIG. 1) revealed minimal smudging, while the glass sample having theeasy-to-clean coating of COMPARATIVE EXAMPLE 4 revealed significantsmudging and streaking of the fingerprint residue.

This visual comparison was also made under ultraviolet light, theresults of which are shown in FIG. 2. As seen in FIG. 2, the glasssample having the oleophilic coating of EXAMPLE 1 (i.e., the sample onthe right-hand side of FIG. 2) revealed minimal smudging, while theglass sample having the easy-to-clean coating of COMPARATIVE EXAMPLE 4revealed significant smudging and streaking of the fingerprint residue.

Thus, the oleophilic coating of EXAMPLE 1 performed significantly betterthan the easy-to-clean coating of COMPARATIVE EXAMPLE 4 from a visualperspective.

Example 7: Mass Transfer, Haze, and Visual Characterization of CoatedGlass Samples

In this example, the smudge-resistance of various coated articles thatwere prepared in accordance with EXAMPLES 1, 2, 4, and 5 was compared.The comparison included a fingerprint residue transfer analysis overtime, a haze analysis over time, and a visual analysis over time.

The sample of EXAMPLE 1 that was characterized was a glass articlecoated with an oleophilic coating formed from an about 25 wt % methylsiloxane solution. For convenience, this sample is described as “25%T-111” in this example.

Two samples from EXAMPLE 2 were characterized. The first was a glassarticle initially coated with an anti-reflection coating comprisingabout 100 nm SiO₂ particles, and subsequently coated with an oleophiliccoating formed from an about 25 wt % methyl siloxane solution. Forconvenience, this sample is described as “100 nm SiO₂ w/ 25% T-111” inthis example. The second sample was a glass article initially coatedwith an anti-reflection coating comprising about 50 nm SiO₂ particles,and subsequently coated with an oleophilic coating formed from an about25 wt % methyl siloxane solution. For convenience, this sample isdescribed as “50 nm SiO₂ w/ 25% T-111” in this example.

The sample of COMPARATIVE EXAMPLE 4 that was characterized was preparedas described therein, and, for convenience, will be described as “EC” inthis example.

The sample of COMPARATIVE EXAMPLE 5 that was characterized was preparedas described therein, and, for convenience, will be described as “SGP”in this example.

The net change in the amount of fingerprint residue that was transferredto the coated articles over time was measured using the touch-and-wipeprocedure described hereinabove. Again, this procedure first entails theuse of a model fingerprint applicator, formed from apolyvinylsiloxane-based, high precision impression material (PresidentJET plus) fingerprint stamp, to apply synthetic sebum to the coatedarticle at about 3 pounds per square inch (psi). This is followed bywiping the applied “fingerprint” using a Crockmeter or a linear abraderfitted with a Crockmeter kit. The wiping step is a modification of theCrockmeter test that is described in ASTM test procedure F1319-94,entitled “Standard Test Method for Determination of Abrasion and SmudgeResistance of Images Produced from Business Copy Products,” the contentsof which are incorporated herein by reference in their entirety as iffully set forth below. Specifically, the Crockmeter or linear abradersubjects the coated article to direct contact with a Crockmeter rubbingtip or “finger” mounted on the end of a weighted arm. Rather than usinga standard crocking cloth, the “finger” is fitted with a portion of anitrile laboratory glove. The wiping step involves contacting the fingerwith the region of the coated article having the syntheticsebum-containing fingerprint with a pressure of about 0.93 psi, andmoving the finger back-and-forth across the coated article. After eachtouch-and-wipe cycle of this procedure, the weight of the coated articleis recorded and compared with the weight of the coated article prior tothe first touch-and-wipe cycle.

The results of the fingerprint residue mass transfer analysis can beseen in FIG. 3, which plots the mass transferred to the coated articlesvs. the number of touch-and-wipe cycles. As shown in the graph of FIG.3, the EC and SGP samples retained the most fingerprint residue overtime. In addition, these samples experienced the greatest changes infingerprint residue mass transfer after each touch-and-wipe cyclerelative to the first cycle. In contrast, after 20 touch-and-wipecycles, the change in fingerprint residue mass transfer for the 25%T-111, 100 nm SiO₂ w/ 25% T-111, and 50 nm SiO₂ w/ 25% T-111 samples wasminimal.

In addition, the change in haze over time was measured for each of thesesamples. This change was measured using the touch-and-wipe proceduredescribed hereinabove, with the exception that, rather than recordingthe weight of the coated articles, their haze was measured after eachcycle of interest. The results of the haze analysis can be seen in FIG.4, which plots the haze of the coated articles vs. the number oftouch-and-wipe cycles. As shown in the graph of FIG. 4, the EC sampleexhibited the highest haze over time. In addition, this sampleexperienced the greatest change in haze after each touch-and-wipe cyclerelative to the first cycle. In contrast, after 20 touch-and-wipecycles, the change in haze for the SGP, 25% T-111, 100 nm SiO₂ w/ 25%T-111, and 50 nm SiO₂ w/ 25% T-111 samples was minimal.

Finally, a visual comparison of the smudge resistance of these samplesover time was also made. This comparison was done using thetouch-and-wipe procedure described hereinabove, with the exception that,rather than recording the weight of the coated articles, their visualcharacteristics was observed after each cycle of interest. The resultsof this visual comparison are shown in FIG. 5. FIG. 5 does not includethe visual characteristics of the 50 nm SiO₂ w/ 25% T-111 sample. Asseen in the top row of FIG. 5, a substantial amount of fingerprintresidue was transferred to each sample during the first touch. As seenin the middle row of FIG. 5, significantly more fingerprint residue canbe seen on the EC sample than on the other three samples after the firstsmudge. Similarly, after 5 touch-and-wipe cycles, significantly morefingerprint residue can be seen on the EC sample than on the other threesamples.

This example illustrates the significant improvement in smudgeresistance obtained from the oleophilic coatings of EXAMPLES 1 and 2relative to the EC sample of COMPARATIVE EXAMPLE 4. In addition, thisexample illustrates that a slight improvement can be obtained over theSGP sample of COMPARATIVE EXAMPLE 5, but without having to apply aseparate film to the substrate, which can cause delamination andbubbling issues over time.

Example 8: Mass Transfer and Haze Characterization of Coated GlassSamples

In this example, the smudge-resistance of various coated articles thatwere prepared in accordance with EXAMPLES 1, 2, 4, and 5 was compared inthe same fashion as described in EXAMPLE 7, with three exceptions.First, this example does not include the 50 nm SiO₂ w/ 25% T-111 sample.Second, no visual comparison is provided in this example. Finally,rather than using a Crockmeter or linear abrader to carry out the wipingstep for each touch-and-wipe cycle, a human fingerprint was used. Greatcare was taken to ensure that substantially the same pressure wasapplied to each wipe.

The results of the fingerprint residue mass transfer analysis can beseen in FIG. 6, which plots the mass transferred to the coated articlesvs. the number of touch-and-wipe cycles. As shown in the graph of FIG.6, the EC and SGP samples retained the most fingerprint residue overtime. In addition, the EC sample experienced the greatest change infingerprint residue mass transfer after each touch-and-wipe cyclerelative to the first cycle. In contrast, after 20 touch-and-wipecycles, the change in fingerprint residue mass transfer for the 25%T-111 sample was minimal. The change in fingerprint residue masstransfer for the 100 nm SiO₂ w/ 25% T-111 and SGP samples over time wassimilar.

The results of the haze analysis can be seen in FIG. 7, which plots thehaze of the coated articles vs. the number of touch-and-wipe cycles. Asshown in the graph of FIG. 7, the EC sample exhibited the highest hazeover time. In addition, this sample experienced the greatest change inhaze after each touch-and-wipe cycle relative to the first cycle. Incontrast, after 20 touch-and-wipe cycles, the change in haze for theSGP, 25% T-111 and 100 nm SiO₂ w/ 25% T-111 samples was minimal.

This example illustrates the significant improvement in smudgeresistance obtained from the oleophilic coatings of EXAMPLES 1 and 2relative to the EC sample of COMPARATIVE EXAMPLE 4. In addition, thisexample illustrates that either a slight improvement over, or similarresults to, the SGP sample of COMPARATIVE EXAMPLE 5 can be obtained, butwithout having to apply a separate film to the substrate, which cancause delamination and bubbling issues over time.

Example 9: Fabrication of Fully-Cured Oleophilic Coatings on Flat GlassSubstrates

In this example, oleophilic coatings were prepared on flat glasssubstrates. The substrates chosen were flat glass sheets having anominal composition of 69.2 mol % SiO₂, 8.5 mol % Al₂O₃, 13.9 mol %Na₂O, 1.2 mol % K₂O, 6.5 mol % MgO, 0.5 mol % CaO, and 0.2 mol % SnO₂.

To form the oleophilic coating, as-received Accuglass® T 11 (111,Honeywell) was diluted in isopropanol to form various solutions rangingfrom about 25 weight percent (wt %) to about 50 wt % methyl siloxane.These solutions were coated onto samples of the glass sheets using thespin-coating process as provided by the manufacturer for use on siliconwafers. The spin-coated samples were cured by using the followingheating cycle: from room temperature, the temperature was ramped up toabout 80 degrees Celsius (° C.) at a rate of about 5 degrees Celsius perminute (° C./min), held at temperature for about 1 min, ramped at a rateof about 5° C./min to about 150° C., held at temperature for about 1min, ramped at a rate of about 5° C./min to about 250° C., held attemperature for about 1 min, ramped at a rate of about 5° C./min toabout 425° C., held at temperature for about 1 hour in nitrogen, andramped down to room temperature at a rate of 10° C./min in air.

Example 10: Contact Angle and Surface Energy Characterization of CoatedGlass Samples

In this example, the contact angles between various fluids and variouscoated articles produced in accordance with EXAMPLEs 1 and 9 werecompared. In addition, the surface energies of such articles werecompared.

Each contact angle measurement was made using a Kruss DSA100 Goniometer.The fluids used for these measurements included de-ionized water(surface tension of 72.3 milliNewtons per meter (mN m⁻¹)), oleic acid(32.8 mN m⁻¹), hexadecane (27.6 mN m⁻¹), and ethylene glycol (47.7 mNm⁻¹). A droplet of a given fluid (about 2 microliters for water, andabout 4 microliters for the organic fluids) was placed on the surface ofa coated article, and the contact angle was measured. This procedure wasrepeated five times, placing the droplets in five different locations onthe surface for each sample. Three different samples were measured assuch, and an average of all 15 measurements was taken as the contactangle for that type of coated article.

The total surface energy of the coated article was determined by takingthe sum of the polar energy component and the dispersive energycomponent. The surface energy was estimated from the contact anglemeasurements of this example using the KRÜSS Drop Shape Analysis programto run a calculation using models such as Wu, Fowkes, and Owens-Wendt.When calculating the surface energy according to each of these models,the software calculated the polar component of the surface energy, thedisperse component of the surface energy, and the total surface energyaccording to each model using the parameters for these modelsestablished by the software program. These estimates were recorded foreach sample, and an average value across 5 samples is reported.

The contact angles and surface energies were measured for a number ofsamples produced under different conditions in accordance with EXAMPLEs1 and 9. TABLE 1 illustrates representative contact angles relative tothe maximum temperature used to cure the oleophilic coating on the glasssubstrate.

TABLE 1 Oleic Ethylene Cure Conditions Acid Glycol Hexadecane WaterEXAMPLE 1: 180° C. 30.2° 59.1° 22.8° 81.3° EXAMPLE 1: 300° C. 29.8°57.5° 24.7° 81.2° EXAMPLE 9: 425° C. 42.7° 73.1° 27.4° 92.9°

As can be seen from the data in TABLE 1, the fully-cured samples ofEXAMPLE 9 were less oleophilic than the partially-cured samples ofEXAMPLE 1, despite having a higher concentration of hydroxyl groups onthe surface (which was separately verified by solid state NMR).

The surface energies of the samples shown in TABLE 1 were calculated,and are shown in TABLE 2, wherein “D” represents the disperse componentof the surface energy, “P” represents the polar component of the surfaceenergy, and “T” represents the total surface energy, and all surfaceenergy values are shown in units of mJ/m².

TABLE 2 Wu Model Fowkes Model Owens-Wendt Model Cure Conditions D P T DP T D P T EXAMPLE 1: 180° C. 24.3 9.5 33.8 25 6 31 23.6 7.4 31 EXAMPLE1: 300° C. 24 10 34 24.7 6.4 31.1 23.6 7.5 31.1 EXAMPLE 9: 425° C. 23.74.5 28.2 24 2 26 22.3 3.2 25.5

As can be seen from the data in TABLE 2, the variations between thesample types are found in the polar component of the surface energy.That is, the disperse component of the surface energies of each type ofsample was substantially similar in each model. When the curetemperature was increased, resulting in a fully-cured methyl siloxane asthe oleophilic coating, the polar component of the surface energy, andthe total surface energy decreased significantly.

This example illustrates the improvement in oleophilicity and surfaceenergy obtained from the partially-cured oleophilic coatings of EXAMPLE1 relative to the fully-cured oleophilic coatings of EXAMPLE 9.

Example 11: Compressive Stress and Depth of Layer Characterization ofCoated Glass Samples

In this example, the changes in compressive stress and depth of layer ofthe chemically strengthened substrates of various coated articles thatwere prepared in accordance with EXAMPLEs 1 and 9 were compared.

The CS of the layer under compression, and the DOL were measured usingan FSM 6000/6000LE glass surface stress meter, which is an optical toolthat generally uses the photoelastic constant and index of refraction ofthe substrate material itself, and converts the measured opticalinterference fringe patterns to specific CS and DOL values. To determinethe amount of change in the CS and DOL values, an initial CS and DOLvalue was obtained for each sample prior to forming the oleophiliccoating. After the curing step, a final CS and DOL value was obtainedfor each sample, and a comparison was made against the initial value. Ineach case, the absolute value of the change is provided.

TABLE 3 illustrates representative changes in CS and DOL data relativeto the maximum temperature used to cure the oleophilic coating on theglass substrate for samples produced under different conditions inaccordance with EXAMPLEs 1 and 9.

TABLE 3 Cure Conditions Change in CS Change in DOL EXAMPLE 1: 200° C.0.2% 0.6% EXAMPLE 1: 300° C. 2.1% 2.5% EXAMPLE 9: 425° C.  25%  17%

As can be seen from the data in TABLE 3, the fully-cured samples ofEXAMPLE 9 resulted in significant changes in the CS and DOL values ofthe layer under compression in the chemically strengthened glasssubstrate. In contrast, the partially-cured samples of EXAMPLE 1exhibited substantially no change in the CS and DOL values after thecuring step.

This example illustrates the improved stability of the surfaceproperties of the chemically strengthened glass substrates from thepartially-cured oleophilic coatings of EXAMPLE 1 relative to thefully-cured oleophilic coatings of EXAMPLE 9.

While the embodiments disclosed herein have been set forth for thepurpose of illustration, the foregoing description should not be deemedto be a limitation on the scope of the disclosure or the appendedclaims. Accordingly, various modifications, adaptations, andalternatives may occur to one skilled in the art without departing fromthe spirit and scope of the present disclosure or the appended claims.

What is claimed is:
 1. A coated article, comprising: a glass orglass-ceramic substrate; and an oleophilic coating having an averagethickness of less than or equal to about 100 nanometers disposed on atleast a portion of a surface of the glass or glass-ceramic substrate;wherein the oleophilic coating comprises a partially-cured siloxanecomprising a plurality of pendant hydroxyl groups; wherein aconcentration of the pendant hydroxyl groups in the partially-curedsiloxane of the oleophilic coating is at least about 25 percent of aconcentration of any pendant hydrogen and hydrocarbon groups in thepartially-cured siloxane; wherein a contact angle between a drop ofoleic acid and the oleophilic coating is about 20° to about 40°; whereina contact angle between a drop of ethylene glycol and the oleophiliccoating is about 45° to about 65°; wherein a contact angle between adrop of hexadecane and the oleophilic coating is about 15° to about 30°;and wherein a contact angle between a drop of water and the oleophiliccoating is about 70° to about 100°.
 2. The coated article of claim 1,further comprising an intermediate layer interposed between the glass orglass-ceramic substrate and the oleophilic coating.
 3. The coatedarticle of claim 2, wherein the intermediate layer comprises areflection-resistant coating, a glare-resistant coating, or acolor-providing composition.
 4. The coated article of claim 1, wherein aconcentration of the pendant hydroxyl groups in the partially-curedsiloxane of the oleophilic coating is greater than or equal to theconcentration of any pendant hydrogen and hydrocarbon groups in thepartially-cured siloxane.
 5. The coated article of claim 1, whereinaccording to a Wu model, a polar component of a surface energy, adisperse component of the surface energy, and a total surface energy ofthe coated article is about 6 milliJoules per square meter to about 15milliJoules per square meter, about 20 milliJoules per square meter toabout 30 milliJoules per square meter, and about 26 milliJoules persquare meter to about 45 milliJoules per square meter, respectively. 6.The coated article of claim 1, wherein according to a Fowkes model, apolar component of a surface energy, a disperse component of the surfaceenergy, and a total surface energy of the coated article is about 4milliJoules per square meter to about 10 milliJoules per square meter,about 20 milliJoules per square meter to about 35 milliJoules per squaremeter, and about 24 milliJoules per square meter to about 45 milliJoulesper square meter, respectively.
 7. The coated article of claim 1,wherein according to an Owens-Wendt model, a polar component of asurface energy, a disperse component of the surface energy, and a totalsurface energy of the coated article is about 5 milliJoules per squaremeter to about 10 milliJoules per square meter, about 20 milliJoules persquare meter to about 30 milliJoules per square meter, and about 25milliJoules per square meter to about 40 milliJoules per square meter,respectively.
 8. The coated article of claim 1, wherein the coatedarticle has a first optical transmittance and a first haze after a firsttouch-and-wipe cycle, wherein each touch-and-wipe cycle comprisestactilely contacting a portion of the coated article with a tactilelytransferred residue and subsequently tactilely wiping at least theportion; wherein the coated article has a second optical transmittanceand a second haze after undergoing a number of touch-and-wipe cycles;and wherein the first optical transmittance and the second opticaltransmittance are substantially similar and/or the first haze and thesecond haze are substantially similar when the number of touch-and-wipecycles is at least
 20. 9. The coated article of claim 8, wherein a massof tactilely transferred residue remaining on the coated article afterat least 20 touch-and-wipe cycles is within 0.4 milligrams of the massof tactilely-transferred residue remaining on the coated article afterthe first touch-and-wipe cycle; wherein the second optical transmittanceis within 3 percent of the first optical transmittance when the numberof touch-and-wipe cycles is at least 20; and/or wherein the second hazeis within 5 percent of the first haze when the number of touch-and-wipecycles is at least
 20. 10. The coated article of claim 1, wherein theglass or glass-ceramic substrate is a chemically strengthened glass orglass-ceramic substrate comprising a layer under compression thatextends from the surface of the glass or glass-ceramic substrate inwardto a selected depth.
 11. The coated article of claim 10, wherein acompressive stress of the layer under compression is about 400megaPascals to about 1200 megaPascals, and the depth of the layer undercompression is about 30 micrometers to about 80 micrometers.
 12. Thecoated article of claim 1, wherein the coated article comprises aportion of a touch-sensitive display screen or cover plate for anelectronic device, a non-touch-sensitive component of an electronicdevice, a surface of a household appliance, or a surface of a vehiclecomponent.